Edit the "includes/xml/cpnav_mobile_enabled.xml" file, and change the "dispalyorder=25" in
Code:
<navgroup text="Mobile Device Style" permissions="canadminsettings" hr="true" displayorder="25">
to be a larger number. Alternatively, you could just delete this fiule from your server altogether, and then the options for this mod will only show up in the vBulletin Options menu - it will no longer have its own menu in the left column of your AdminCP.
Hope this helps